Conventionally, .22 rimfire ammunition cartridges comprise a cylindrical casing closed at one end and open at the other, the open end being crimped to a bullet, usually of lead. The closed end or head of the casing defines an annular flange or rim containing a priming composition which ignites by a rimfire strike and the hollow body of the casing contains a propellant which is fired by the ignition of the primer causing rapid expansion of hot gases to force the bullet from its seating.
The bullet conventionally has a cylindrical body portion, which may be solid or hollow and a tapered, curved, or so-called ogive, portion leading from the cylindrical body to the nose of the bullet. The body portion usually has external knurls to hold lubricant which is provided to prevent material being stripped from the circumference of the bullet as it is expelled along the barrel of the gun.
It has previously been proposed, see for example, U.S. Pat. No. 3,866,536, to provide a flat nose on a bullet so that the ogive curve is in effect shortened and cut off at the nose end.